llvm_tools: add internal CL support to cros_cls

Some llvm-next CLs (e.g., manifest updates) need to be internal.
Supporting those here is straightforward.

BUG=b:333462347
TEST=repo upload

Change-Id: I6ca14cfce2e086743476fe0eb059b9172736707e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/5450238
Reviewed-by: Jordan Abrahams-Whitehead <ajordanr@google.com>
Tested-by: George Burgess <gbiv@chromium.org>
Commit-Queue: George Burgess <gbiv@chromium.org>
2 files changed